Body Mass Index Calculator

Quick BMI calculator by height, weight and age

Use this Body Mass Index Calculator to quickly estimate your BMI and check whether your weight is broadly within healthy guideline ranges.

Weight unit kg lb

cm ft/in

Age:

Your Body Mass Index

Normal weight for your height

*Results are for informational purposes only. If you are concerned about your health or weight, speak to a doctor or qualified healthcare professional.

BMI calculator for children & teenagers

How to use the Body Mass Index Calculator

1. Enter your details

Enter your weight in kilograms and your height in centimetres in the calculator fields.

2. Calculate BMI

Click the calculate button and the BMI calculator will work out your Body Mass Index.

3. Review your result

View your BMI score and see which weight range it falls into.

Limits of Body Mass Index

Body Mass Index (BMI) is a popular and useful indicator, but it has limitations. BMI is an estimate and does not measure body composition, such as how much of your weight comes from muscle, bone, or body fat.

Because body types differ, BMI should be used alongside other measurements rather than as the only way to assess healthy weight.

Factors such as age, sex, ethnicity, muscle mass, body fat distribution, and activity level can affect how BMI should be interpreted.

For example, an older person can have a healthy BMI while still carrying a higher proportion of body fat, especially if they are less active.

On the other hand, a younger person or an athlete may have a higher BMI due to greater muscle mass while still being healthy.

Your ideal BMI range

For most adults, a BMI between 18.5 and 24.9 is often used as a general healthy range for weight relative to height.

However, there is no single BMI that fits everyone, because age, sex, ethnicity, muscle mass, and activity level can all influence what is healthiest for you.

Use this Body Mass Index Calculator to understand where you currently sit, then consider other factors such as waist measurement, fitness, and overall wellbeing.

If you are unsure what your result means for your situation, a clinician can help you interpret it.

For adults aged 18 to 64

Your height	Ideal weight
4 ft 11 in / 150 cm	93 – 123 lb / 42 – 56 kg
5 ft 1 in / 155 cm	98 – 132 lb / 44.5 – 60 kg
5 ft 3 in / 160 cm	105 – 141 lb / 47.5 – 64 kg
5 ft 5 in / 165 cm	111 – 150 lb / 50.5 – 68 kg
5 ft 7 in / 170 cm	118 – 159 lb / 53.5 – 72 kg
5 ft 9 in / 175 cm	126 – 169 lb / 57 – 76.5 kg
5 ft 11 in / 180 cm	132 – 179 lb / 60 – 81 kg
6 ft 1 in / 185 cm	140 – 188 lb / 63.5 – 85.5 kg
6 ft 3 in / 190 cm	148 – 198 lb / 67 – 90 kg
6 ft 5 in / 195 cm	155 – 209 lb / 70.5 – 95 kg
6 ft 7 in / 200 cm	163 – 220 lb / 74 – 100 kg

Risks linked to overweight

Carrying excess weight can increase the risk of several health conditions, including:

High blood pressure
Higher LDL cholesterol and lower HDL cholesterol
Type 2 diabetes
Higher triglycerides
Coronary heart disease
Stroke
Gallbladder disease
Osteoarthritis

Sleep apnoea and breathing problems
Some cancers, including cancers of the womb, breast, colon, kidney, gallbladder, and liver
Lower quality of life
Mental health concerns such as depression and anxiety
Physical pain
Difficulty with certain physical activities and daily functions

Maintaining a BMI below 25 kg/m² is often recommended, but personal health guidance can vary. If you are considering changes to diet or exercise, it can help to speak with a healthcare professional.

Risks linked to underweight

Being underweight can also carry health risks, including:

Poor nutrition
Vitamin deficiencies
Anaemia
Osteoporosis and higher fracture risk
Weakened immune function
Growth and development concerns, especially in children and teenagers

In women, being underweight can contribute to hormonal changes that affect the menstrual cycle and may increase pregnancy risks. Underweight can also make recovery after surgery harder and may be a sign of an underlying condition, including eating disorders.

If you think you or someone you know is underweight, speak to a doctor, especially if the cause is not clear.

F. A. Q.

How do I calculate my Body Mass Index?

To calculate BMI, you need your weight in kilograms and your height in centimetres. Enter them into this Body Mass Index Calculator and you will get your BMI score instantly.

Is BMI always an accurate measure of health?

BMI is a useful screening tool, but it is not a complete picture of health. It does not account for muscle mass, bone density, or how body fat is distributed, so it should be interpreted with context.

Does BMI change with age?

BMI is calculated the same way at any age, but its meaning can change. Older adults often carry more body fat at the same BMI, so additional health measures can be helpful.

Is BMI the same for men and women?

The BMI formula is the same for men and women. However, women often have a higher body fat percentage than men at the same BMI, which can affect interpretation.

What if my BMI is high but I am muscular?

A high BMI can be caused by muscle mass rather than excess body fat. If you are very active or muscular, consider other measures such as waist size or body fat percentage for a clearer picture.

How can I improve my BMI?

Improving BMI usually involves long term habits like balanced nutrition, regular activity, and good sleep. If you want a more personalised plan, consider speaking with a clinician or using tools that estimate daily energy needs to guide calorie targets.